From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A6C7CC433E3 for ; Fri, 24 Jul 2020 13:41:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8F5A820714 for ; Fri, 24 Jul 2020 13:41:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727050AbgGXNlS (ORCPT ); Fri, 24 Jul 2020 09:41:18 -0400 Received: from verein.lst.de ([213.95.11.211]:35719 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726235AbgGXNlR (ORCPT ); Fri, 24 Jul 2020 09:41:17 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id B8C5168AFE; Fri, 24 Jul 2020 15:41:14 +0200 (CEST) Date: Fri, 24 Jul 2020 15:41:14 +0200 From: Christoph Hellwig To: Amit Pundir Cc: Nicolas Saenz Julienne , Christoph Hellwig , Marek Szyprowski , Robin Murphy , David Rientjes , linux-rpi-kernel@lists.infradead.org, jeremy.linton@arm.com, iommu@lists.linux-foundation.org, lkml , John Stultz , Sumit Semwal Subject: Re: [PATCH] dma-pool: Do not allocate pool memory from CMA Message-ID: <20200724134114.GA3152@lst.de> References: <550b30a86c0785049d24c945e2c6628d491cee3a.camel@suse.de> <011994f8a717a00dcd9ed7682a1ddeb421c2c43f.camel@suse.de> <01831596e4a2a6c9c066138b23bd30435f8e5569.camel@suse.de> <6db722947546221ed99d3f473f78e1a6de65d7d6.camel@suse.de> <0dc1e922bf87fa73790e7471b3974528dd261486.camel@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Yes, the iommu is an interesting case, and the current code is wrong for that. Can you try the patch below? It contains a modified version of Nicolas' patch to try CMA again for the expansion and a new (for now hackish) way to not apply the addressability check for dma-iommu allocations. diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 6bc74a2d51273e..ec5e525d2b9309 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -3,7 +3,9 @@ * Copyright (C) 2012 ARM Ltd. * Copyright (C) 2020 Google LLC */ +#include #include +#include #include #include #include @@ -55,6 +57,31 @@ static void dma_atomic_pool_size_add(gfp_t gfp, size_t size) pool_size_kernel += size; } +static bool cma_in_zone(gfp_t gfp) +{ + phys_addr_t end; + unsigned long size; + struct cma *cma; + + cma = dev_get_cma_area(NULL); + if (!cma) + return false; + + size = cma_get_size(cma); + if (!size) + return false; + end = cma_get_base(cma) - memblock_start_of_DRAM() + size - 1; + + /* CMA can't cross zone boundaries, see cma_activate_area() */ + if (IS_ENABLED(CONFIG_ZONE_DMA) && (gfp & GFP_DMA) && + end <= DMA_BIT_MASK(zone_dma_bits)) + return true; + if (IS_ENABLED(CONFIG_ZONE_DMA32) && (gfp & GFP_DMA32) && + end <= DMA_BIT_MASK(32)) + return true; + return true; +} + static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, gfp_t gfp) { @@ -68,7 +95,11 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size, do { pool_size = 1 << (PAGE_SHIFT + order); - page = alloc_pages(gfp, order); + if (cma_in_zone(gfp)) + page = dma_alloc_from_contiguous(NULL, 1 << order, + order, false); + if (!page) + page = alloc_pages(gfp, order); } while (!page && order-- > 0); if (!page) goto out; @@ -251,7 +282,11 @@ void *dma_alloc_from_pool(struct device *dev, size_t size, continue; phys = gen_pool_virt_to_phys(pool, val); - if (dma_coherent_ok(dev, phys, size)) + /* + * Only apply the addressability check for dma-direct. + * This is a nasty hack and won't work e.g. for arm. + */ + if (get_dma_ops(dev) || dma_coherent_ok(dev, phys, size)) break; gen_pool_free(pool, val, size);